DDX3X and autism spectrum disorder: Heterozygous missense or loss-of-function mutations in DDX3X are also implicated in intellectual disability and autism-spectrum disorders in females (Iossifov et al. 2014; Snijders Blok et al. 2015; Yuen et al. 2017; Takata et al. 2018; Wang et al. 2018; Ruzzo et al. 2019; Scala et al. 2019; Lennox et al. 2020), with the severity of phenotype correlating with the degree of reduction in DDX3X catalytic activity (Lennox et al. 2020).